help me work out glitches in my new 306

[tylerrocks]

NEW PROBLEMS!!! 07-02-06

I have a problem with my new engine. It surges at Idle, when I put a timing light to it, timing surges from 8-20* the engine seems to run best at 13-14*. Anyways I took it for a test drive (bout a 1/4 mile) and revved it to around 4000. It felt good untill 3rd gear when shortly thereafter the engine quit. It has done this a couple times. The engine starts back up and still quits after 3rd even if driving normally. I tried just keeping it alive in 2nd and with my foot steady on the pedal the car seemed as the power was comming on and off making the car pull/jerk intermitatly with a rhythm if that makes any sence, kinda like Wa Wa Wa Wa. If I let up on the pedal it dies. Also, when checking total advance with a light, the light will cut out at about 30*. I have tightend the dist hold down clamp tight. let me know if I can explain anything better or if you need any more info.

Thanks,
Tyler

 

[Pbum5]

make sure all of you vacum lines are pluugged or conected on the carb.

 

[D.Hearne]

Check your vacuum advance if it has one. Busted diaphram and it won't add it's advance, you'll just get the centrifugal. Also check your fuel supply making sure the flow is there to supply the carb.

 

[jcode68]

Did you use the early or late firing order when you wired your plug wires? If you get this wring, you will be firing on only 4 cylinders (ask me how I know). When you set the timing, make sure you remove the vacuum line from the vac advance and you want to be somewhere between 12-14 degrees base timing at idle once the car is warmed up. If your timing is jumping around, I'm not sure what would cause that since it sounds like you are working with a fresh engine (new timing gearset & chain) etc.

 

[tylerrocks]

thanks for the replies it was a vaccume leak. Here's another question. When I checked the total advance (after plugging the vac leak) it was about 45. I know, too much. I had to pull initial timing down to 6* just to get total to 38*. I understand that I can change springs to get a diffrent advance curve, where are these springs located? it is an HEI distributor.

 

[gsxrken]

45 degrees with vacuum advance connected to ported vacuum might not be too much.
The rule of thumb is 32-36 initial and centrifugal. The vacuum can add another 10 or 12 degrees in part-throttle high vacuum situations, where because of the low load, the engine can handle it. If your plugs look good and you are not pinging, you might be OK where you are.

 

[tylerrocks]

Ok, I'm still trying to get this thing running right. I replaced the intake gaskets to rid myself of a vacume leak. Now i can start my car and it will (fast)idle at about 15 in. vacume. It will idle like this for about a minute then slow down, get rough and die. I can keep it alive by revving, but only for so long. Sometimes when I hit the gas the engine quits firing (bog?), when this happens I can keep the engine alive by letting off the gas, but only for so long. I cant keep the engine alive for more than a couple of minutes.

The carb is a speed demon 650, mech. secondaries. The float bowl level used to be fine, but searching out bugs, me and craig (friend who helped assemble the motor, has decades of experience) went through and cleaned the carb (bought used) with berrymans, and air pressure. Since the I haven't been able to get the float level correct. Even with the needle and seat valve opened all the way the bowl level is still below the glass. When I told craig about this, he suggested a new powervalve and an oil change. The oil did have droplets of clear liquid that I assume to be gas, and coolant from the gasket change. I replaced a 95 powervalve with an 85 as suggested by craig, the jets are 70. Still didn't help the float level.

I checked the plugs, not wet just have black soot on them. I am pulling my hair out with this. Come on :SNSign:

 

[D.Hearne]

Powervalve on a Holley is usuallly a 65. I set the floats initially with em off the carb. Adjust till they're parallel with the bowl. Once it's running they're usually dead on, only occasionally need a slight tweak.

 

[tylerrocks]

should I try a 65? dose 85 sound like too much? this is really discouraging because I'm out of ideas.

Tyler

 

[D.Hearne]

I run a 65 on a 750, and did as well on a 650 DP and a 600, on both a 302 and 390 and they worked there.

 

[D.Hearne]

Does by any chance the BG carb have "rock" inlet filters behind the fuel inlet fittings? Holleys do. I bought the 750 I have in my Ranger and the primary side rock filter was plugged solid with red mud. Secondary side was clean as a whistle. Know what "rock" type filter looks like?

 

[tylerrocks]

No, not exactly, but I can imagine. I will look at them tomarrow when I go to the shop. They would be located behind where the fuel lines go into the carb?

Tyler

 

[dennis112]

Tyler, is your HEI distributor a Duraspark?

 

[tylerrocks]

No sir, its a mallory.

 

[2nd Mustang]

I went through a similar problem that you're having. Mine turned out to be the throttle shaft on the carb being worn out causing a vacuum leak. At first, the carb wouldn't idle at a 1000 rpms, but would at 1500 rpms, so I bought a rebuild kit, blew out all the passages, etc. It then idled good at 1000, but barely. Fiddled with it more, then just bit the bullet and bought a new Holley. Tweaked the mixture screws and haven't looked back for over two years now.

 

[D.Hearne]

I went through a similar problem that you're having. Mine turned out to be the throttle shaft on the carb being worn out causing a vacuum leak. At first, the carb wouldn't idle at a 1000 rpms, but would at 1500 rpms, so I bought a rebuild kit, blew out all the passages, etc. It then idled good at 1000, but barely. Fiddled with it more, then just bit the bullet and bought a new Holley. Tweaked the mixture screws and haven't looked back for over two years now.

I've had several Holleys with worn throttle shaft bushings, but instead of buying new, If you'll watch ebay, there's usually a few new base plate assemblys there. I've bought three and all ran about $125.

 

[D.Hearne]

No, not exactly, but I can imagine. I will look at them tomarrow when I go to the shop. They would be located behind where the fuel lines go into the carb?

Tyler

Remove the fuel line from the bowl, then unscrew the fitting in the bowl the line screws into. Holley puts the rock type filter in that cavity behind the fitting. It's a copper colored (probably is copper) filter made up of what looks like small bb's crushed into shape. Rochester's used them too.

 

[tylerrocks]

Well I never saw a rock filter. But, I did find another potential problem. After trying everything I could think of, I took the fuel line apart at one joint and hotwired the fuel pump. After about ten seconds of pumping, I finally saw a trickle of fuel coming out. I'm talkin barley fast enough to make a stream. I checked the fuel lines with compressed air and they seem good. The only thing is, the pump used to fill up the bowls no problem, now it barley flows. what gives?

Tyler

 

[D.Hearne]

Where's your pump? At the engine or tank? I see a few Stangs lately here in the forum having clogged lines from trash in old tanks. The electric I run on my Ranger has a filter before the pump. When it starts to starve the carb, that's the one always plugged up.

 

[tylerrocks]

In front of the tank. So i should have a filter before the pump too?